Valve for rock drills



and efiicient construction.

Patented Jan. 1, 1952 VALVE FOR Rook DRILLS 7 Jacob E. Feucht, Garfield Heights, Ohio, assignor to Le Roi Company, Milwaukee, Wis., a corpo' ration of Wisconsin Application May 19, 1948, Serial No. 28,024

6 Claims. (ohm-19) This invention relates broadly to fluid actuated rock drills, but more particularly to a motive fluid distributing valve therefor.

One object of this invention is to provide a rock drill with a fluid distributing valve of simple Another object of this invention is to produce a fluid distributing valve for rock drills which affords maximum stroke of the rock drill piston and results in a more efiicient tool. s

Another object of this invention is to produce 'a'fluiddistributing valve for rock drills capable of rapid and positive distribution of the motive fiuid alternatively to the ends of the rock drill cylinder for effecting a fast and efiicient reciprocation'of the rock drill piston.

Other objects and advantages more or less ancillary to the foregoing reside in the specific construction and 'aggroupment' of thelelements peculiar to this structure, as will become apparent from a more complete examination ofthis specification. Inthe drawing: Figure l is a longitudinal sectional view of a portion of a rockdrill embodying the invention. Figure 1A is an enlarged view-of a-portion of the valve mechanism as shown in Figure 1; Figure 2 is a view corresponding to Figure-'1 but showing the valve and piston in another position ,1 a

t Figure 2A is an enlarged view ofaportion-of theevalve mechanism as shown in Figure Figure 3 is. a cross sectionalviewtaken in a planeindicated byline 3-3 in Figure 2. Figure 4 is .a cross sectional view taken in a. plane indicated by line4-4 in Figure Referring tothe drawing in which like symbols Q I designate corresponding parts throughout the severalv views, [0 represents the; main cylinder of a rock drill, which cylinder is normally closed its interior accurately machined to form a piston chamber it within which is reciprocably mounted a piston is. As shown in the drawing, the right hand portion of the piston chamber I6, herein-' 0 by. a back head I2 and tappet cases [4,- and has 1 and '24 extending rearwardly from the bore '22. 'I'he'counterbore 23'is made with a flat bottom 25, hereinafter referred to as a front valve seat, which seat is diametrically extended beyond the normal wall of the counterbore 23 by a circular groove 26' maintained in constant communication with the rear portion of the piston chamber '16 through a"plurality of rear'inlet' ports 28, one of which is shown in Figures 1 and 2; The bottom ofzthe counterbore 24 is constantly vented to the exterior of the cylinder through a vent port 21. I Mounted'for free reciprocation within thevalve casing 2| but in fluid tight engagement with the walls of the counterbores 23 and 24', there is a sleeve valve 29 having its'front end 30 perfectly machined forfiuidtight engagement with the valve seat 25. Fora short distance from'the front end 30, the diameter of the valve 29 is reduced to provide a front lifting or shifting area 3|.

In the casing 2|, there is a stationary valve bushing 32 whichhas its rear end portion closely fitted within the counterbore 24 and its front end portion reduced to fitclosely within the central bore 22 of the casing 2|, thereby maintaining the valve bushing in perfect alignment with ,the easing. Intermediate its ends, the valve bushing is provided with two cylindrical reduced portions 33 and 34 fitting within the interior of the valve 29 in sliding engagement therewith, and forming two annular-areas 35 and 36, the area 35 being accuf rately machinedto form a fiat rear valve seat engageableiby'ythe adjacent rear end 31 of the valve; The length of the bushing reduced portion 33 is made somewhat shorter than the cor:- responding depth of the valve, so that the area 36 :is' not engageable by the corresponding step or area 38 ofthe valvepwhich area 38 forms a rear shifting area; in communication with the piston chamber l6 through a kick port 39.

' The bushing 32 is'internally machined to provide a chamber 40 which opens into a chamber M provided within the back head [2. These two after referred to as the front or front portion, has

extending thereinto the shank 20 0f a tappet (not shown). on which i the piston I8 is adaptedv to deliverits impacts, which are transmitted therefrom to-the cutting tool in the usual manneri Fitted within the other end 'portion o'f the cylinchambers form a reservoir for motive fluid which may be admitted therein through a supply port 4 2 controlled by a throttle valve 43. This throttle valvemay be ofany suitable type and is provided with a central bore or passage 44 to which motive fluid is admitted from a source ofsupply.

; Adjacent the front end30/of the valve 29; the bushing 32 is chamfered to form with thevalve seat 25 and the interior of the valve wherrposider I0,-hereinafter designated as the rear or rear portion of the piston chamber, there is a valve mechanism which includes a stationary 'valve cas ing 2|. havinga central bore 22'e'xtending through the front end thereof and two'counterbores 23 tioned as shown; in Figures 1 and 1A, fa second motive flu'id supply chamber 45, which chamber is in constant communication with the chamber 40 through inlet-ports 46: i v

supp yi g motive fluid to the rear valve while the back piston chamber is similarly enlarged by blind ports 51 opening thereinto adja: cent the valve casing 2|. Intermediate its ends.

but located closer to the front than the rear end thereof, the piston chamber [6 isprovided with an exhaust groove 52 which is connected-to the* exterior of the cylinder through one or mere ex i,

haust ports 53.

Referring now to the'bperation vof this valve mechanism, it will be understood thatwith the throttle valve 43 open, motive fluid such as compressed air will flow into the first inlet chamber 4I through the port 42. With the piston. l8 and valve 29 positioned as shown in Figures 1 and 1A, motive fluid from, the interior ofv the bushing 32'willflow to the rear valve seat 35 and act on the rear end or rear holding area 31 of. the valve for maintaining it .in itsforward position, With thevalve in its forward position, motive fluid from the valve seat 35 is free to flow into the front portion of the piston chamber [6 through the front inlet ports 48 and groove 49.

In the position of the piston l8 shown in Figure 1, that is engaged with the tappet shank'20 to deliver its impact thereon, the piston hasuncovered the'exhaust groove 52, enabling communication of the rear portion of the piston chamber 16 with the exterior of the cylinder and a free return stroke of the piston, which stroke is effected by theaction of the motive fluid admitted into the front portion of the piston chamber.

During its return or back stroke, the piston will first cover the exhaust groove 52 and the inletend of the kick. port 39, and thereafter .will compress air remaining within the rear end portion ofthe piston chamber I 6. The air thus compressed will act on the valvefront shifting areai3l, it being admitted theretothrough the rear inletports 28, tending. to shift the valve rearwardly. However, motive fluidis still active onthe valve rear holding are-s31, andsincethis area is;greater]than the area 3|, the valve will remain in theposition shown in Figures 1 and 1A until the front end of the piston uncovers the exhaust groove 52 to enable exhaust. of the motive fluid from the front end of the piston chamber 16; This sudden exhaust will cause a drop of pressure of the motive fluid acting on the valve rear holding area 31, al-' lowing the valve toshift to the position shown in Figures 2 and 2A. I

In'this new or rear position of the valve, motive fluid from the second supply chamber willact on the valve front' holding area 30 and front shifting area 3| to maintain the valve in its rear position. Simultaneously, motive fluid from the same chamber 45 will flow through the rear inlet ports 28 into the rear end of the piston chamber IE to act on the piston for driving it forward against the tappet shank 20.

During its forward stroke, the rear end of the piston will uncover the inlet end of the kickport 39, thereby allowing motive fluid from the piston chamber I6 to flow to the valve rear shifting area shifting area 3| and front holding area 30, the

valve will immediately shift to its forward position. During the end of its forward stroke, the piston will also uncover the exhaust groove 52 to allow exhaust of the motive fluid previously admitted into the rear end of the piston chamber [6, as well as exhaust of the n otive fluid from the valve rear shifting area throughthe kick port 39, which port is now in communication with the exhaust groove 52 through the piston chamber [6.

The forward stroke of the piston will end as the piston strikes the tappet shank 20.

As previously explained, the valve is held in its forward position by the action of the motive fluid on the'valverear holding area 31, while motive fluidis again admitted into the front end of the piston-chamber l3 through the front inlet ports of..parts and modifications of structural-detail may be resorted towithout departing from the scope and spirit of the invention as herein claimed. I

I claim:

1. In a ,fluid actuated. rock; drill, a c linder having a piston chamber, a pistonreciprocable in said chamber, an exhaust port for -the; -piston chambercontrolled by said pistoma valve casing having opposed front and rear flat annular valve seats,. a sleeve valve reciprocable within said casing, means internally of said valve for constantly supplying motive fluid to said seats, front and rear inlet ports leading from; the correspondingly named valve seats into the -front and rear, portions of said piston chamber for alternativelyadmitting motive fluid therein to, effect reciprocation of-saidpiston, the opposed-ends of; said valve being movable into and outi of fluid tight engagement with said valve seats, ,by -virtue of the reciproation of theyalve for controlling admission of. the motive fluid into :the front and rearportions of said piston-chamber, the endsof said valve when moved out of said fluid tight.engage-. ment forming holding areas subjectedto. the action ,of the motive fluid constantly; supplied to said valve seats for holding the valve out of said fluid tight; engagement, and means effecting re? ciprocation of. said valve including aninternal shifting area.:-on:.said valve intermittently sub-, jected temotive ,fluid from- .the 'rear portion of said. piston-chamber when said piston reaches a predetermined position'therein during its forward stroke forlshiftingsaid valve in a .position preventingsupply of. motive fluid 'to said rear inlet ports,'and .an external shifting area .on said valve subje cted; to:=-;fluid compressed. within. the rear portioniofgsaid piston chamber during therear stroke of said piston .tendingQto shift said valve ina: position preventing supply of motive fluid to. said front inlet ports, 4 this last movement vof the valve oecurringafter the pressure of the motive :fluid acting ;on the valve-holding. area :for maintainingthe zvalvein the-position to be shiftedfrom has been reduced .by virtue of the exhaust ofthe motive fluid fromthefront end portion of said piston chamberthrough-said'exhaust port. r

2.;In- B-rflllid, actuated rock @drill; a :cylinder havinga:pistonchamber, apiston reciprocable in rageeogvuv said chambenean exhaust p0lti-ff0l' the piston chamber controlled bysaid piston, a valve casing having opposed frontarid rear flat" annular valve seats, a sleeve valvereciprocable within said casing, meansinternally ofsaid valve for constantly supplying motive fluid to said seats,

front and rear inlet ports leading from the corfect reciprocation of said piston, the-opposed ends of said valve being movable into and out of fluid tight engagement with said valve seats by virtue of the reciprocation of the valve for controlling admission of the motive fluid into the front and rear portions of said piston chamber, the ends of said valve when moved out of said fluid tight engagement forming holding areas subjected to the action of the motive fluid constantly supplied to said valve seats for holding the valve out of said fluid tight engagement, and means effecting reciprocation of said valve including opposed internal and external valve shifting areas, the internal area being intermittently subjected to valve shifting motive fluid from the rear portion of said piston chamber during the forward stroke of the piston and the external area being intermittently subjected to valve shifting fluid compressed in said rear portion of the piston chamber by the piston during its rearward stroke.

3. In a fluid actuated rock drill, a cylinder having a piston chamber, a piston reciprocable in said chamber, an exhaust port for the piston chamber controlled by said piston, a valve casing having opposed front and rear flat annular valve seats, a sleeve valve reciprocable within said casing, means internally of said valve for constantly supplying motive fluid to said seats, front and rear inlet ports leading from the correspondingly named valve seats into the front and rear portions of said piston chamber for alternatively admitting motive fluid therein to effect reciprocation of said piston, the opposed ends of said valve being movable into and out of fluid tight engagement with said valve seats by virtue of the reciprocation of the valve for controlling admission of the motive fluid into the front and rear portions of said piston chamber, the ends of said valve when moved out of said fluid tight engagement forming holding areas subjected to the action of the motive fluid constantly supplied to said valve seats for holding the valve out of said fluid tight engagement, and means effecting reciprocation of said valve including opposed internal and external valve shifting areas, said external area being intermittently subjected to valve shifting fluid compressed in the rear portion of the piston chamber by the piston during its rearward stroke, and a kick port leading from said internal area to said piston chamber, said kick port being controlled by said piston for admitting valve shifting motive fluid to said internal area.

4. In a fluid actuated rock drill, a cylinder having a piston chamber, a piston reciprocable in said chamber, an exhaust port for the piston chamber controlled by said piston, a valve casing having opposed front and rear flat annular valve seats, a sleeve valve reciprocable within said casing, means internally of said valve for constantly supplying motive fluid to said seats, front and rear inlet ports leading from the correspondingly named valve seats into the front and rear portions of said piston chamber for alternatively admitting motive fluid therein to effect reciprocation of said piston, the opposed ends of said valve being mov- 1 able 1 into and. out of fluid tight engagement. with "said'yalve'seats by virtue of therreciprocationof the valvezfor controlling admission of the motive fluid into-the front and rear portionsof said piston chamber, the ends of. said valve when :moved out of said fluid tight engagement forming holding areas subjected to, the action of the motive fluid constantly supplied to said .valve seats for holding the .valve out .of said fluid; tight ,engagement; and means effecting reciprocation, of

I said valve including opposed internal and external valve shifting areas, a kick port leading from said internal area to said piston chamber, said .kick

port being controlled by .athe piston during its forward'stroke forintermittently admitting valve shifting motive fluid to said internal area, said external area being intermittently subjected to valve shifting fluid compressed in the rear portion of the piston chamber by the piston during its rearward stroke, said external area after the shift of the valve by virtue of the compressed fluid acting thereon being also subjected to motive fluid constantly admitted to one of said valve seats for holding the valve away from said one valve seat.

5. In a fluid actuated rock drill, a cylinder having a piston chamber, a piston reciprocable in said chamber, an exhaust port for the piston chamber controlled by the piston, a valve casing having a front flat annular valve seat, a valve bushing in said casing having a rear flat annular valve seat, a sleeve valve reciprocable in said casing and on said bushing capable of end engagement with said valve seats, a first motive fluid supplying chamber internally of said bushing, front inlet ports leading from said last chamber to the rear valve seat and therefrom to the front end portion of said piston chamber for supplying motive fluid thereinto to effect the rearward stroke of said 'piston, the supply of motive fluid through said 7 front inlet ports being shut off by engagement of the valve with said rear valve seat, a second motive fluid supplying chamber externally of said bushing, ports affording constant communication between said first and second chambers, means for supplying motive fluid from said second chamber into the rear portion of said piston chamber for effecting the forward stroke of said piston including rear inlet ports, the supply of motive fluid through said rear inlet ports being shut off by engagement of the valve with said front valve seat, and means for effecting the reciprocation of said valve including opposed valve shifting areas alternatively subjected to valve shifting fluid from said piston chamber.

6. In a fluid actuated rock drill, a cylinder having a piston chamber, a piston reciprocable in said chamber, an exhaust port for the piston chamber controlled by the piston, a valve casing having a front flat annular valve seat, a valve bushing in said casing having a rear flat annular valve seat, a sleeve valve reciprocablein said casing and on said bushing capable of end engagement with said-valve seats, a first motive fluid supplying chamber said bushing, front inlet ports leading from said last chamber to the rear valve seat and therefrom to the front end portion of said piston chamber for supplying motive fluid thereinto to effect the rearward stroke of said piston, the supply of motive fluid through said front inlet ports being shut off by engagement of the valve with said rear valve seat, a second motive fluid supplying chamber externally of said bushing, Ports affording constant communication between said internally of mam? inlet *ports, the Supply: of motive :fluid through 1 5 said rea'fi inlet ports-being shut; o'fiibyengagement of the valve with said front va1ve'seat;=andrmeans "for eflectihgihe reciprocation; -of. 'said valve including opposed valve shifting areas alternatively subjected to'valve shifting fluid from said-piston:

-chamber and holding-areas for saidvalvetormed by the ends thereof: arid-subjected :to motive fiuid fibm-said supplychambers for temporarily holdlnsthe walveat the endof its strokes.

I JEREFERENGES CITED ii The fbl1ow1ng""referenc'es are"of"record1nthe "'fllebf this patent:

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